Photo by: Warren Watkins
FILE - In this Jan. 1, 2011 file photo, a worker with U.S. Environmental Services, a private contractor, picks up a dead bird in Beebe, Ark. where more than 3,000 dead black birds fell from the sky on New Year's Eve. Some saw the event and other recent wildlife die-offs as real signs as something sinister, either biblical or environmental. The reality, say biologists, is that they happen all the time. (AP Photo/The Daily Citizen, Warren Watkins, File)

Robert Mueller’s special counsel investigation into Russian meddling in the 2016 election has cost $6.7 million during the first four and a half months of the probe. Click to see past independent counsel investigations guilty of racking up high bills.